Field of the Invention
The present invention relates to a conductive polymer composition containing a polyaniline-based conductive polymer, a coated article using the same, a patterning process, and a substrate. In particular, the present invention relates to a conductive polymer composition that is suitably used for prevention of electrification of a resist in lithography using ultraviolet light, electron beam, or the like, an article having an antistatic film formed by using the same, a patterning process using the conductive polymer composition, and a substrate obtained by the patterning process.
Description of the Related Art
Conventionally, in the fabrication process of a semiconductor device such as IC and LSI, microprocessing by lithography using a photoresist has been employed. This is a method of etching a substrate by using a resist pattern as a mask, in which the resist pattern is obtained by irradiating a thin film with light to induce crosslinking or decomposition reaction, thereby changing the solubility of the thin film, and subjecting the same to development treatment with a solvent or the like. In recent years, as a semiconductor device advances toward high integration, high-precision microprocessing using a beam with short wavelength has been required. The development of lithography using electron beam has been progressed for next generation technique because of its short-wavelength properties.
The lithography using electron beam has a specific problem of electrification phenomenon (charge-up) during exposure. This is a phenomenon that when a substrate to be irradiated with electron beam is coated with an insulating resist film, it is charged by accumulation of electric charge on or in the resist film. An orbit of incident electron beam is bent by the electrification, and therefore the precision of drawing is significantly reduced. Accordingly, an antistatic film to be applied on an electron beam resist has been investigated.
To control the reduction in drawing precision, Patent Document 1 discloses a composition containing a composite of an aniline-based conductive polymer and a polyacid, and H2O; the composite of an aniline-based conductive polymer and a polyacid in amount of 5 to 10% by mass can readily form a film by spin coating, which exhibits sufficient antistatic effect with a film thickness of 150 nm, and this antistatic film can be removed and washed with H2O.
However, when the antistatic film is formed on a chemically amplified resist, the shape or the sensitivity of the resist may change. For example, an acid produced by exposure is neutralized by a component in the antistatic film, whereby an exposed part of a positive resist is insolubilized during development, or an exposed part of a negative resist is partially dissolved during development. Otherwise, an acid component in the antistatic film makes an unexposed part of a positive resist partially soluble during development, or an unexposed part of a negative resist insoluble during development.
Since the chemically amplified resist does not have resistance to most organic solvent, an aqueous antistatic agent to be formed on the resist is often used. However, the surface of the chemically amplified resist is hydrophobic, so that the aqueous antistatic agent is unlikely to be applied. Therefore, it is necessary to add a surfactant or the like, but the addition of the surfactant may cause a mixing layer on the resist surface. In the mixing layer, the effect of an acid produced in the resist and an acid component in the antistatic film is enhanced after drawing, which leads to problems of changes in shape and sensitivity of the resist.
Patent Document 2 discloses a conductive composition containing a basic compound and a composite of a polyaniline-based conductive polymer substituted with an acidic group, and mentions the application to electrolytic capacitor, and an effect of enhancing the heat resistance and the conductivity under high-temperature atmosphere.